Develop and implement a standard protocol for a double blind study to determine whether the regular administration of aspirin to people who have had a documented myocardial infarction will result in a significant reduction in total mortality over a three year period of follow-up. Year I - planning/preparation of forms to be used; planning for recruitment; completion of the protocol and beginning of patient recruitment. Year II - continued recruitment of subjects and beginning of patient follow-up. Years III and IV - follow-up studies on all participants. Year V completion of the follow-up and phase out of the study.